Fluid pressure tool



May 31, 1932. E. w. STEVENS 1,350,954

. FLUID PRESSURE TOOL Filed May 16. 1930 2 Sheets-Sheet 1 I N VEN TOR. [award I1. Jze wens ATTORNEY.

y 1932- E. w. STE VENS 1,860,964

FLUID PRESSURE TOOL Filed May 16, 1930 2 Sheets-Sheet 2 I N VEN TOR. fawaro Wife was Jaw miwm A TTORNEY.

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Patented May 31, 1932 sure PATEN'r orm EDWARD STEVEN'S,"OF-DETROIT, MICHIGAN, dASSIGNOR TO CHICAGO 1 INETIJMZ AIEH'JT" TOOL COMPANY, 01 YORK, N. Y., -A GORPORATION' OF NEW JERSEY FLUID rnnssuaniroor.

Application filed May 16, 1930. Serial No. 452,827. I

7 This invention relates to percussive tools operated byfiuid} pressure such as compressed air and more particularly to light weight rock drillsofthetypehaving a valve'for controlling the distributionofithe-motive fluid.

Amongthe Objects of the invention are to develop a simplified construction for such tools with avery compact valve housing, to reduce the number of valve' iparts to-a. minimum; to avoid-sharpbends in the supply passages which lead to the ends of the piston chamber, to reduce thecost of manufacture and the expense of lip-keep, and in general to improve ;prior devices in respect: to efficiency "and s'ervlice. p f f p I I In order to illustrate the invention one concrete embodiment thereof is shown in the accompanying drawing in which: 7

Fig. 1 is a longitudinal sectional view showing the hammer piston beginning its downward orpower stroke;

2is a sectional View similar to Fig. 1 showing the piston beginning itsrearward or non-working stroke; p Q

3 is a detail sectional view substantially on:-theline 33 :ofFig. 2; and

.Fig; 4 is a sectional/view similar to Fig.

the porting arrangement. V i r The embodiment of the invention chosen for the purpose .of illustration comprises an automatic rotation .rock drill which 'is con,

ventional astomost ofitszfeatures. The drill comprises .a cylinder5 within which "recipro- 'cates a hammer piston 6 controlling mainexhaust port's v 7 and and adapted to impart blows directly to ardrill steel 9supportedin l a rotarychuck10 mounted inafront head 11 secured to cylinder 5. The opposite'end of the l.cylinder is closed by cylinder ring 12,

and handled?) which together support the rifle bar'zl i which cooperates with rifie nut 15in piston .6 .to impart rotation to cylinder .5, which :rotary impulse is transmitted by the piston to chuck 10 .by the usual splined con:

' nection.v V

; 'JC-ylinder .5 has .at one side an externally projecting :boss'16 which is preferable integral with the cylinder. The boss is generally cylindrical in shape asindicated in Figs.

3and 4 and provides opposed arcuate valve seats. Inthe peripheral surface of these valve seats are ports 17 and 18 from which extend substantially straight'but downwardly inclined passages 1 7aand 18a opening into theports 17 and '18, is a ring valve 21 which sliclably engagesthe base of boss '16 on the one hand and the interior of cap 19 on theother. Cap 19 has-a threaded bore 19;?) to which the motive "fluid inlet conduit ,(not shown) is secured with the resu'lt that the pressure fluid is admitted to "the valve chamher within 'valve 21. The clearancefbetween 7 boss 16 and cap 19 about inlet 19b is "restricted, as clearlyshown in'Figs. l and '2, fora purpose presently to be described.

As indicated in Fig. 3,"th'e shape of boss 16 is such "that, when valve 21 engages one. of the valveseats, it'le'aves an elliptically shaped area through whichthe motive fluid may pass,-

freely across the other seat-to "the then open port in the. present instance port :17 and asimilar situation obtains whenthe valveis in its opposite position. In orderto get a freely acting valve, means are provided for utilizing a portion" of the livemotive fluid to assist in breaking the seal over either port 17orport 18 when closed by valve 21. For this purpose balancing reliefs areprovided in the valveseats on both sides of ports 17 and 18. One;

way of making thesereliefs isto indicatedat 16a on the boss 16.

The operation of the hammer will be apparent to those skilled in the art and may be grind flats as briefly stated as follows: With the parts in the position shown in Fig, 1 live motive fluid from inlet 19?) is passing through; the elliptical area at the left off boss 16 through port 18, passage 18a, and portl8bfinto the rear end of the piston chamberto drive pis ton 6 on its forward or working stroke. "Ports lOO ' motive 17b, passage 17a, and port 17 are vented to atmosphere through main piston controlled exhaust port 8 and port 17 is sealed off from the inlet by valve 21. As the piston moves forward to strike its blow, it seals main exhaust 8 but uncovers main exhaust 7 with the result that the pressure is relieved in the rear end of the piston chamber as well as in passage 18a and, due to the restriction provided between boss 16 and cap 19 which limits the amount of motive fluid passing to port 18,

there is a distinct drop in pressure on the internal surface of the valve at this point. At the same time the air trapped and compressed in front of piston 6 is forced through port 176, passage 17a, and port 17 against the internal surface of the valve over port 17, which pressure is assisted by live motive fluid from the inlet port bearing on the internal surface of the right side of the valve through reliefs 16a on either side of ports 17. Accordingly, thevalve is thrown to the position shown in Figs. 2 and 3 thereby scaling port 18 and uncovering1 port 17, thus admitting the live to drive piston 6 rearwardly. As the piston seals main exhaust port 7 and uncovers main exhaust port 8, the pressure obtaining on Jzhe opposite sidesof valve 21 are reversed and the valve is thrown to the original position shown in Fig. 1. r

' In the modification shown" in Fig. 4the porting arrangement is such that the inlet ports to the piston chamber, 18s and 172, are on the same centre axial line instead of at opposite sides of such a line as in Fig. 3. To produce this effect without leng'theningthe passages or making undesirable bends in the same, the seats engaged by valve 21 are displaced about 30 from the position shown in Fig. 3 so that the valve moves an ularly of cylinder 5 rather than axially. ith this arrangement the cross passages 18g and 17y, which connect the valve controlled ports 18m and 17:12 with the piston chamber ports 182 and 172, are at an angle to theaxis of the cylinder as well as at a downward inclination. By using plain ports at17w and 18% rather than the undercut arcuate ports shown in Figs. 1, 2, and 3, relief areas 16aof greater extent are possible than in the form first described. Such larger reliefs make the valve more sensitive to changes m pressure.

From the above it will be apparent that the present invention is characterized by a minimum number of very simple valve parts. Moreover thethrottling of the incoming fluid by the close approach of cap 19 to valve boss 16and the use of balancing reliefs on the valve seats permit an extremely sensitive control of the movement of the valve. The

construction also provides for passages to the piston chamber under control of the valve v d through passage 17a and port 17b to the front end of the piston chamber cylinder having a boss on the side thereof,

a cap extending over said boss to provide a valve chamber therearound, a ring valve encircling said boss and slidably engaging the base of the same and the interior of said cap, said boss having ports in the peripheral surface thereof for control by said valve with passages leading therefrom to the opposite ends of said cylinder, and means for admitting motive fluid to said valve chamber.

2. In a fluid pressure percussive tool, a cylinder having a boss on the side thereof, ports in the opposite sides of said boss and cross passages leading straight from [said ports to the opposite ends of said cylinder, a scap extending over said boss to provide a valve chamber therearound, a ring valve encircling said boss and movable transversely thereof to control said ports in alternation,

' and means for admitting motive fluid to said providing opposed arcuate valve seats, a port 7 in each valve seat, cross passages leading from said ports straight to the opposite ends of said cylinder, inlet means for motive fluid encircling said boss to provide a valve chamber, a ring valve encircling said boss and movable thereon to control said ports in alternation, said boss having portions of its seats cut away to provide relief areas for utilizing live. motive fluid to assist in shifting the valve. I

4. In a fluid pressure'percussive tool, a cylinder having a boss on the side thereof providing opposed arcuate valve seats, a port in each valve seat, cross passages leading from said. ports straight to the opposite ends of said cylinder, an inlet member for motive fluid encircling said boss to provide a same axial center line, inlet means for motive fluid encirclingsaid boss to provide a valve chamber therearound, and a ring valve encircling said boss and movable thereon to control said ports in alternation.

6. A fluid pressure percussive tool comprising a cylinder, a hammer piston reciprocable therein, said cylinder having a cylindrical boss projecting. from the side thereof with ports and passages leading to the opposite ends of the piston chamber, means enclosing said boss toprovide a valve chamber, a ring valve encircling said boss and slidably engaging With its opposite edges the base of the boss and said means respectively, said valve being movable relative to said boss to control said ports in alternation and to distribute motive fluid to the piston chamber, said enclosing means admitting motive fluid to the interior of said valve and cooperating with said boss to restrict the quantity passing to said ports.

7 A fluid pressure percussive tool comprising a cylinder, a'hammer pi'stonreciprocable therein, said cylinder having a cylindrical boss projecting from the side thereof with ports and passages leading to the opposite ends of the piston chamber, a member inclosing said boss to provide a valve chamber therearound, a ring valve encircling said boss and movable relative thereto, to control said ports in alternation, means for admltting mo-.

tive fluid to the interior of said valve, said ports and passages leading to the opposite ends of the piston chamber a ring valve mov ably mounted upon said boss to control said ports in alternation, a motive fluid inletmember inclosing said valve and having a portion only slightly spaced from said boss to restrict the motive fluid flow thereover.

Signed by me at Detroit, in the county of member and said boss cooperating to limit;

the quantity of motive fluid passing to one of said, valve controlled ports. 7

8. A fluid pressure percussive tool comprising a cylinder, a hammer piston reciprocable therein, said cylinder having a cylindrical boss projecting. from the side thereof with ports and passages leading to the opposite ends of the piston chamber, a member inclos-- ing said boss to provide a valve chamber therearound, a ring valve encircling said boss and movable relative thereto to control said ports in alternation, said member providing an inlet for motive fluid, and means adjacent said inlet for effecting a restriction in the quantity of motive fluid controlled by said valve..

9. Afluid pressure percussive tool comprising a cylinder, a hammer piston reciprocable therein, said cylinder having a cylindrical boss projecting from the side thereof with ports and passages leading to'the opposite ends of the piston chamber, an imperforate ring valve movably mounted on said boss to control said ports in alternation, and a motive fluid inlet member secured to said cylinder, said valve cooperating with said member to confine the admitted. motive fluid to the interior of said valve.

10 A fluid pressure percussive tool comprising a cylinder, a hammer piston reciprocable therein, said cylinder havin'ga cylindrical boss projecting from the side thereof with I 

